Ignition composition



Sepit. 19, 1939. BURROWS 2,173,271

IGNITION COMPOSITION Filed July 50, 1957 u 'l i l I I l I I x 1 I I ILawzon A. Burrows INVENTOR.

A TTORNEYS.

Reiterates! gept. 119, 3%39 2,2732%1 myrrh snares enter @FFHE2,l'i3;2'ill roNlI'rroN oosmosmoa Lawton A, Burrows, Wenonah, N. 3.,asslgnor to IE. ll. du lPont de Nemo & (Company, Wilgton, Del acorporation oil Delaware Application 30, 1937, Serial No. 156,483 12Claims. (on. 52 -2) The p t invention e tes to blasting initiunderstood,however, that the compositions indiators, and in particular to new andimproved i cated constitute merely preferred embodiments nitioncompositions for use in various types of of my invention for the purposeof more adequate said initiators. illustration, and that the scope ofthe invention 5 As is well known, ignition compositions for use is notto be limited by the details set forth in these in blasting initiatorsgenerally, must be highly examples.

sensitive to heat in order to give effective per- Example I formance.Unfortunately, the materials known to the art which possess thisrequired sensitive- Per cent ness to heat, likewise tend to be sensitiveto shock, Ptflsium chlorate w friction or static charges. Consequently,such calcmm hmphmme 30 materials are hazardous and present serious Pymsmokeless powder problems, not only during the course of manufac- Thiscomposition is desirably employed as a ture, b in the ha of the finishedproduct loose ignition charge in the various types of blast- 35thereafter. ing'initiators. It may be grained according to 35Furthermore, the ignition compositions known any of the well knownprocedures in order to fato the art are frequently unsatisfactory forthe cllitate loading into theinitiator shell.

reason that they are incompatible with certain of Example H the metalsand alloys commonly employed for l Per cent so. ini iator shells, andhave a corrosive efiect on Calcium hypophospmte so said shells Potassiumnitrate 45 The object of my invention is to provide a new sulfur 10 andimproved ignition composition which is relatively insensitive to shock,friction and static composit o is ew s highly desirable as electricity.A further object is to provide such a a loose charge i blastinginitiators generally- 25 composition whichis satisfactory for use withthe Example 11 nzetasllslalnd alloys coonly employed for initi- Per centa or e s. A still further object is to provide an ignition compositionwhich is readily ignited and gfimfigi ggg I y possesses uniform andrapid burning properties. calcium suicide 20 3 Other objects will bediscussed as the invention is Nitmstamh further described hereinafter. I

I have found that these objects are accomme foregoing compwmonisespecially suitable plished according to the'present invention, by the$8 an ignition cflmposition r initiators h preparation of ignitioncompositions comprising concave plug type. An inappreciable amount of 35v calcium hypophosphite and an omdizing agent, nitrostarch is employedas a binder and to accom- While I find that satisfactory ignitionoomposip sh the parti selatlnization 0f the compositiontions are formedfrom calcium hypophosphite and Any 0f the solvents commonly p y f r Suchan oxidizing agent alone, I prefer to employ compurpose may be used toassist in this gelatlnizapositions comprising calcium hy o ho hit antion. The resulting compositions show no tend- 4o oxidizing agent, andat least one readily ignltible ency to become friable or to disintegrateon storfuel. Many different types of fuels are suitable age, but remainin position in the concave plug, as including both organic and inorganicfuels. As compact coherent massexamples of organic fuels, I may employground In the manu actu e of electric q l I prefer smokeless powder andthe like. As inorganic o e p y apre e charge consisting of c fuels, Iprefer to employ finely divided atmos- 0 1ml hypoph flh t Potassiumchlorate, and at pherically stable metals such as magnesium, zirleastone of the metallic or alloy fuels mentioned conium, and aluminum,atmospherically stable in the foregoing, such as magnesium, calciumsilialloys such as antimony-iron, ferro-silicon, silicide or the like.This base-charge is preferably con-manganese carbon, calcium silicide,and ignited by means of a loose superposed charge metalloids of group VIof the periodic table. consisting of calcium hypoph phi e and pPreferred ignition compositions according to sium chlorate. my inventionand prefered adaptations of the By way of more exact description,reference is same to the various types of blasting initiators, made tothe accompanying drawing. in which are set forth in the followingexamples. It is Fig. 1 shows an ordinary fuse type blasting cap.

Fig. 2 shows an electric blasting cap of the concave plug type, whileFig. 3 shows an electric squib of the closed type. Similar numeralsrefer to similar parts throughout the several views.

Referring to Fig. 1, I designates the shell of the initiator which ismade of gliding metal or other suitable material, 5 the base chargepreferably tetryl, t a primary charge, e. g. mercuryfulminate enclosedin the capsule 3, said primary charge being superimposed on the basecharge. 2 representsthe ignition composition of my invention, whichcomposition is to be fired by the flame from a fuse. Referring to Fig.2, the ignition composition 2 of the present invention is shown in aconcave plug 9, in close relationship with the primary charge 4, whichis superimposed on the secondary charge 5. The ignition composition 2 isfired by means of an electric current passing through the leading wires6. bringing to incandescence the bridge wire it] which passes thru theignition composition. The leading wires are held in place by means ofthe conical bridge plug 9, with the waterproofing composition 8 abovethe bridge plug and the sulfur composition 1 at the top Fig. 3 showsanelectric squib having the loose ignition composition 2, superimposedon a pressed base charge I I, which preferably includes calciumhypophosphite, a fuel and an oxidizing agent. The ignition composition 2is fired by electrically heating the bridge wire III, to incandescence.

It is apparent from the foregoing that the calciumhypophosphite-containing compositions according to the present inventionare satisfactorily adapted for use as ignition compositions in thevarious types of blasting initiators. The presence of the calciumhypophosphite as a chief ingredient imparts to the resulting compositionthe highly desirable properties of low sensitiveness to 'shock andfriction, but without any diminution ing devices in which saidcompcsitiom are cmployed.

It is understood that the various examples cited herein are given by wayof illustration. Many variations may be made without departing from thespirit and scope of my invention. For example, the composition recitedfor use in a concave plug is suitable not only as the ignitioncomposition of a blasting initiator, but also as the ignitioncomposition of a delay squib. I therefore, intend to be bound only bythe following claims.

I claim:

1. An ignition composition comprising calcium hypophosphite and anoxidizing agent.

2. An ignition composition comprising calcium hypophosphite, anoxidizing agent and a fuel.

3. An ignition composition comprising calcium hypophosphite, anoxidizing agent and an inorganic fuel.

4. An'ignition composition comprising calcium hypophosphite, anoxidizing agent and an atmospherically stable metal.

5. The ignition composition of claim 4 wherein the atmosphericallystable metal comprises magnesium.

6. An ignition composition comprising calcium hypophosphite, anoxidizing agent and an atmospherically stable alloy.

'7. The ignition composition of claim 6 wherein the alloy comprisescalcium silicide.

8. An ignition composition comprising calcium hypophosphite, anoxidizing agent and a metalloid of group VI of the periodic table.

9. The ignition composition of claim 8 wherein the metalloid comprisessulfur.

10. An ignition composition comprising calcium hypophosphite, anoxidizing agent and an organic fuel.

11. The ignition composition of claim 10 wherein the organic fuelcomprises ground smokeless powder.

12. An electric squib which includes a base charge comprising calciumhypophosphite, an oxidizing agent and a readily ignitible inorganicfuel, and a superposed ignition charge comprising calcium hypophosphiteand an oxidizing agent.

LA'WTON A. fEiiiTFtH-QWS.

